Hi,
Actually we would like to use the AFE in Weight Scale and Bioimpedance Measurements. We meet some issues into the calibration resistors step.
Currently we have 4 calibration resistors, and we choose (though registers) which one we put in the circuit. This is complicated to use because the resistors are in parallel so the value of the resistors is not the one we know. Therefore we removed 2 resistors: R87 and R88 to have only R86 and R89. Also, we replaced the 0R jumpers R105, 107, 111 and 113 by 100nF capacitors as they are on the main circuit but not the calibration one.
10kR is too high for the AFE, therefore we use 200R and 750R for calibration. To check the linearity, we add a resistor between 470R and 604R on the main circuit. Each measure is: we measure the calibration resistors, we measure the real resistor, and we check linearity.
The issue is: we don't have linearity. R89 is always super high, like saturated, whatever the value of the resistor we put.
Please find the schematic and the values sended by the AFE4300.
Please could you the firmware to initialisaze, calibrate and caculate the bioimpedance?
I have already read the different documents.
Could you share all the documents about the Evaluation Kit of the AFE4300?
Thanks a lot
Guillaume
